Russia's Interstate Aviation Committee (MAK) confirms the identity and says a joint civil-military commission will investigate the accident, which took place at about 10:50 Moscow time at the military airport north of Smolensk.

Vladimir Putin, the Russian prime minister, has signed a decree to establish the commission. Among those the Government has named to its panel are Russia's transport minister and federal transport chief, air traffic control head, air force commander, and the president of Tupolev.

Poland's presidential office confirms that Kaczynski, his wife Maria, and dozens of senior Polish Government officials, politicians, and military personnel were on board the flight from Warsaw.

It states that preliminary information suggests the aircraft struck trees at the end of the runway while attempting a go-around. Weather conditions at the airport are unconfirmed, but local meteorological stations report fog in the vicinity.

The number of landing attempts made before the accident is unclear. Unconfirmed reports state that the crew had been offered a diversion.

Poland's presidential office says it is still awaiting official confirmation of the number of occupants and casualties, but has published a list of passengers - headed by Kaczynski - who checked in at Warsaw.

Russia's emergency ministry states that eight crew members and 88 members of the Polish delegation were on board, and that there is no evidence of survivors.

It says the crash occurred 300m from the runway at Smolensk's Severni military airport. The runway at Severni is aligned east-west and is 2,500m long.

The loss of so many senior officials in a single accident echoes the loss of a Polish EADS Casa C-295 during a landing approach to Miroslawiec in January 2008, which killed several high-ranking military personnel.

Kaczynski, who has led Poland for five years, was due to attend a memorial service to mark the 70th anniversary of the 1940 massacre of Polish prisoners at Katyn.